Nutrition

Question 1

B12 important for which reactions, and if low what goes up/down?

Answer 1

1. Homocysteine to Methionine
2. Methyl THF to THF

Plus is used in mitochondria for MMA (methylmalonic acid) to make succinyl CoA

so in def, both Homocysteine & MMA increase in blood

Question 2

Process of B12 absorption

Answer 2

1. Cobalamin dissolves from animal protein in gut pH
2. Binds to haptocorrin for protection “transcobalamin 1”
3. Pancreatic proteases dissolve from Haptocorrin in duodenum
4. Increased pH from gut means binds to IF
5. In Ileum, absorbed across Cuban receptor of enterocyte
6. In enterocyte, lysosomes cleave IF and cobalamin
7. In blood, rejoins haptocorrin (inactive), but also Holotranscobalamin II (active)